Conventionally, disposable sanitary products of the type in question comprise an absorbent pad, consisting normally of cellulose fibres, which is enclosed in a soft cover. The cover is fashioned from a permeable inner sheet of non-woven fabric and an impermeable outer sheet of polyethylene, bonded one to another and presenting shaped elasticated edges.
The absorbent article presents a front part and a rear part furnished with closure elements serving to ensure that the article will remain correctly and stably in place when put on by the wearer.
In particular, the closure elements consist in discrete strips or tabs of sheet elastomer material having at least one surface coated with adhesive and attachable thus to the front part of the absorbent article. The single article is furnished with a pair of such closure elements, positioned one on either side, by which the article is closed up and held in place, hugging the hips of the wearer.
Generally speaking, the closure elements are placed in pairs directly onto respective articles advancing continuously along a transport line.
More particularly, closure elements are obtained from a continuous strip of elastic material, fed through a first cutting station at which it is divided longitudinally to generate two continuous and parallel bands. The longitudinal cut follows a wavy line in such a way that one edge of each band will present a succession of projecting portions (each constituting a single closure element) alternated with recessed portions.
Thereafter, the two bands are advanced parallel one with another through a train of guide rollers, which also serve to align the two bands by accelerating or retarding the feed rate of at least one or the other. In this way, each projecting portion of one band will occupy a position facing a projecting portion of the other band.
Aligned thus, the bands advance toward a second cutting station at which they are divided into single segments, each presenting a respective projecting portion, in such a way as to obtain a succession of closure elements ordered in pairs. The pairs of elements are then directed onto the transport line along which the absorbent articles advance, and each successive pair is sealed to the rear part of a respective article.
In reality, machines of the prior art for manufacturing absorbent articles are affected by notable drawbacks.
Firstly, the machines in question are excessively cumbersome, due principally to the size of the components by which the single closure elements are formed. In effect, the closure elements are obtained from a pair of continuous bands that take up considerable amounts of space and require numerous rollers for conveying purposes.
Owing also to the nature of the elastic material from which the continuous strip is made, the bands tend not be accurately aligned.
In practice, the bands are tensioned by the guide rollers and this causes them to become staggered one relative to another, so that when cut transversely and fashioned into single closure elements, imprecisions will appear.